Mrp4, A New Mitogen-Regulated Protein/Proliferin Gene; Unique in This Gene Family for Its Expression in the Adult Mouse Tail and Ear

The study investigated the response of mitogen-regulated protein/proliferin (mrp/plf) gene family transcripts to tumor promoters in SENCAR mice. After applying tumor promoters like TPA and BPO to the skin, researchers observed significant increases in mRNAs for genes such as ornithine decarboxylase, junB, and egr1, particularly in response to TPA. Although mrp/plf-mRNA was not detected in Northern blot hybridizations, it was identified using RT-PCR in most TPA-treated and some BPO-treated animals. The predominant mRNA species were plf1 and mrp3. The study concluded that mrp/plf-mRNA was differentially expressed in response to tumor promoters and could serve as a biomarker for tumor-promoting effects in chemical carcinogenesis.